How come people from other countries cant pronounce other peoples names properly?

There are rules for decoding Words that should not be applied to names, but often are. For example, the name Juan might be assigned the sounds /j/ /oo/ /a/ /n/ in English, but /h/ /w/ /a/ /n/ in Spanish.

Also, some language have a harsh, guttural sound to their symbols while others are more like soft or hard sounds not made using the throat.